Spring and air cushion



May 7, 1940- D.. A. GREENE Er AL SPRING AND AIR CUSHION Filed Aug. 8, 1958 2 Sheets-Sheet 1 5. @Nwm Tf# m @Tm msdn .cA mm N ww .nu

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' May 7, 1940.

Patented May 7, 1940 UNITED STATES PATENT OFFICE SPRING AND AIR CUSHION tion of Michigan Application August 8,

7 Claims.

This invention relates to a spring and air cushion.

The prior art is replete with spring and air cushions. The Stubnitz Patent No. 2,031,745

' 5. shows a spring and air cushion comprising a border frame which is bridged by a plurality of cross slats and an imperforate bottom plate of fiber board positioned upon the slats within the border frame and provided with a small clearance between the periphery and the frame so that air can pass into and out of the seat cushion through the clearance between the edge of the bottom plate and the frame. This air and spring cushion has proved unsatisfactory in use because it has been found impossible to definitely control the amount of air passing into and out of the cushion between the edge of the bottom plate and the frame. The inability to definitely control the amount of air leakage is due primarily to two factors, first, there is always a slight variation in size of production frames which necessarily gives a different clearance between different frames and their respective bottom plates, and secondly, since the bottom plates are generally made of fi- 25A brous material, such as fiber board and cardboard, they also vary in size depending upon conditions of humidity. In a dry atmosphere the flber board bottom plate will shrink or contract and in a moist atmosphere expand. Due to this 30.` expansion or contraction a diaphragmmeasuring approximately 45 inches in length sometimes varies in length as much as TQ@ of an inch.

The type of spring and air cushion shown in the Stubnitz Patent No. 2,031,745 has also been 35, unsatisfactory because in a two passenger cushion where the interior air space or compression chamber is larger less leakage is desired than is necessary in the smaller one passenger cushions. According to the Stubnitz patent the clearance between the edge of the bottom plate and the lower frame allows more clearance than is necessary in the two passenger cushion. In a smaller one passenger cushion where more leakage is desired than in the two passenger cushion, due to the restricted air space, the spaced bottom plate of the Stubnitz patent allows less air leakage than is necessary. In other words, the amount of air leakage necessary in a spring cushion does not vary in direct proportion to the volume of the interior of the cushion.

It is an object of this invention to overcome the above disadvantages of the spring and air cushion heretofore known in the art and produce a combination air and spring cushion in which the amount of air compression and the amount of air 193s, 'serial No. 223,604

owing out of and into the interior of the cushion can be definitely. controlled.

In the drawings:

Fig. 1 is a vertical section through the spring and air cushion.

Fig. 2 is a horizontal section through the spring and air cushion looking down upon the perforated bottom plate.

Fig. 3 is an enlarged vertical section through the lower border frame and bottom plate with a full line showing of the bottom plate being inserted into the border frame and with a dotted line showing of the bottom plate in position within the border frame.

Fig. l is a detail vertical sectional view through the border frame and bottom plate showing the spring assembly mounted on the bottom plate.'

Fig. 5 is an enlarged fragmentary horizontal section looking down upon a corner of the bottom plate and lower border frame.

Referring more particularly to the drawings there is shown a seat comprising a lower border frame l bridged by a plurality of cross bars 2 which support a bottom plate 3 and a spring assembly 4. 'I'he spring assembly comprises a plurality of springs 5 which are held together at the top by the wire frame 6 and at the bottom by the metal channel members 9 which are clamped on to the springs. The spring assembly is provided with a padding and then covered by 'a suitable fabric or leather trim cover` which is drawn taut and secured in any suitable manner, such as by the clips I0, to the bead il -on the lower border frame. The trim cover is referenced 22.

In order to definitely control the amount of air flowing into and out ofthe interior of the seat cushion it is proposed to use a bottom plate preferably, although not necessarily, of fibrous material, such as fiber board, cardboard, or KB board, which has a practically air-tight seal at all times with the lower border frame regardless of the change in dimensions of the bottom plate due to expansion or contraction or variations in size of the lower border frames due to manufacturing conditions and imperfections. This has been achieved by providing a bottom plate having an edge portion which is held at all times against the inside face of the border frame and that portion of the cross bars which fits against the inside face of the border frame. Therefore expansion and contraction of the bottom plate will merely increase and decrease respectively the angle at which the edge of the bottom plate is held against the border frame but will not cause the bottom overall dilerence in dimensions ofthe fiber boardk l2 due to expansion and contraotioncaus'ed by variations in relative humidity of the atmosphere and the amount of moisture absorbed by lthe board can also be easily determined, it is essential, that the overall dimensions'of the ap I3 and ber board I2 should be such that the :anwill v always be held against the inside face ofthe border frame'. The width ofthe flapcan vary'but' as above stated, the flap' should alwaysbe 'sufliciently wide .so that under all conditions of humidity it will be held against the' inside face. of theA border frame and theportion of Vthe cross bars extending upwardly along the inside face of the border frame and in air-sealing relation with these members.

VA s'shown in Figs. l and 3, the overall dimensions, width and length of the' ber board I2 and peripheral iiap I3 is greater than the inside dimensions of thevframe. Preferably this difference should at least equal the difference in the dimensions of the bottom plate dueto extreme expansion and extreme contraction. By forcing the bottom plateinwardly into the border frameand down upon the cross bars the periph# eralap I3 is bent' upwardly and held under stress against the inside' face ofthe border frame. The bottom plate canbe held against theslats in any suitable manner.

Preferably the spring assembly is positioned upon the bottom plate and then held down upon the bottom plate by the clips 1. As herein shown it will be noted Vthat the spring assembly cooperates with the clips to hold the bottom plate against the cross bars and thus the iap I3 'is held against the inside face of the lower border frame to effect an airtight seal. Preferably the bottom plate can be scored on its underside as at I4 to facilitate the hinging action ofthe flap I3.

From the above it isrevident that as the bottom plate expands or contracts the flap I3 being held under stress acts like a hinge and at all times seats against the inside face of the border frame to eiect an air-tight'sealf Preferably the bottomv plate and vin particular the flap I3 is out as at I6 and II on each side of the portion I9 of the slat which engages the inside face'of the border frame to eiect' a better air-tight seal' between the flap and this portion of the slat.

The flap will lay against the` inner wall of the border frame at anrangle depending upon the variation and size of the diaphragm and frame. The acute angle A between flap I3 and the inside face of the border frame will vary as the bottom plate expands and contracts due to atmospheric conditions but the flap will always effect a sube stantially air-tight seal with the border frame.

After the bottom plate is thus positioned within the lower border` frame and the cushion is properly trimmed, the exact amount of air'leakage required for best riding comfort in any given cushion may then be obtained by cutting a suf- Since the variation in size of the flcient number of proper sized holes. 2| in the bottom plate.

We claim:

l. A spring and air cushion comprising a. border frame, a bottom plate having one or more perforations therein and a resilient peripheral portion, the overall. size of said bottom plate and resilient edge portion being greater than the inside dimensions of said frame, a spring assembly, above the bottom plate, a cover enclosing said spring assembly, the said bottom plate being positioned within the frame whereby the resilient edge portion is held against the inside of the border frame at an angle and at all times seals the samewliereby air flows into and out of said cushion substantially only through said perforations.

2; A spring and air cushion comprising a border frame, cross bars bridging the frame, a ber board bottom plate having an edge flap positioned within 'the frame upon the cross barswitlrthe flap held at an angle against the inside faceof the border frame, ai spring assembly above'the bottom'plate; one or more perforations in the bottom piate, a cover for said spring assembly secured to the frame whereby now oi'air into and out ofthe cushion is controlled by said'perforations and the flap seals against the border frame at all times regardless of expansion and contraction of said bottom plate.

3. A spring and air cushion comprising a border frame defining an opening, a perforated bottom plate positioned within the frame having a yieldable edge portion held at an acute angle against the' inside face of the borderframe with a practicaliy air-tight seal, a spring assembly positioned above the bottom plate, means for securing the spring assembly to the bottom plate, a coverfor'- the spring assembly whereby expansion'and contraction of the bottom plate respectively decreases andincreases the acuteness of the said angle between the yieldable edge portion and the border frame and the air-tight seal between these members is maintained andsubstantially all air passing into and out of the interior of the cushion will pass through said perforations.

4. A spring and air cushion comprising a border frame dening an opening, a perforated bottom plate positioned within the frame having a hinged flap held at an acute angle against the inside face of the border frame with a practically airtight seal, al spring assembly positioned above the bottom plate, means for securing the spring assembly to the bottom plate, a cover for the spring assembly whereby expansion and contraction ot the bottom 'plate respectively decreases and increases the acuteness of the said angle between thehinged flap and the border frame and the air-tight'seal between these members is maintained and substantially all air passing into andA out oi 'the interior of the cushion will pass through said perforations.

5. A spring and air cushion comprising a border frame defining an opening, a perforated bottom plate positioned within'the frame having a hinged flap he-ld at an acute angle against the inside face of the border Aframe with a practically air-tight seal, the bottom plate being scored along the line where the flap joins the bottom plate to facilitate hinging of the flap, a springV assembly positioned above the bottom plate, means for securing the spring assembly to the bottom plate, a cover for the spring assembly whereby expansion and contraction of the bottom plate respectively decreases and increases the acuteness of the said angle between the hinged flap and the border frame and the air-tight seal between these members is maintained and substantially all air passing into and out of the interior of the cushion will pass through said perforations.

6. A spring and air cushion comprising a border frame, a perforated bottom plate positioned within the frame and having a yieldable edge portion held at an angle against the inside face of the border frame with a substantially air-tight seal, a spring assembly positioned upon the bottom plate having a lower edge portion which extends adjacent the edge of the bottom plate, means for securing the spring assembly to the border frame whereby the spring assembly stresses the yieldable edge portion of the bottom plate to at al1 times eiect a substantially air-tight seal between Said yieldable edge portion and the bottom frame regardless of expansion and contraction of the A:at

bottom plate, and a cover for enclosing said springy assembly.

'7. A spring and air cushion comprising a. border frame, a perforated bottom plate positioned within the frame and having a resilient ap held at an angle against the inside face of the border frame with a substantially air-tight seal, a spring assembly positioned upon the bottom plate having a lower edge portion which extends adjacent the edge of the bottom plate, means for securing the spring assembly to the border frame whereby the spring assembly stresses thev resilient nap of the bottom plate to at all times effect a substantially air-tight seal between said resilient flap and the bottom frameregardless of expansion and contraction of the bottom plate, and a cover for enclosing said spring assembly.

DANIEL A. GREENE.

JOHN M. CAUGHEY. 

